From the prior art it is known to apply safety designations on workpieces. Usually, these safety designations are applied by a laser on the surface of the workpiece. These safety designations or markings are also called “data matrix codes” (DMC).
From the German publication DE 10 2008 000 503 A1, a method for verifying data matrix codes is known. During a processing procedure, a marking is applied on workpieces. The workpiece then can be permanently identified with reference to this marking. For verifying the applied marking, a camera is connected to the laser marking system. The data matrix code applied to the workpiece is read with this camera and compared with the desired code and verified.
The German publication DE 10153943 A1 discloses a laser writer and a method for applying a matrix code on an object. The device contains a laser for generating a laser beam and a deflection unit for focusing and guiding the laser beam within a marking field on the object or workpiece. For reading the matrix code generated on the object, the laser writer also contains a reading device. The field of view of the reading device can be set by the deflection unit at least to one part of the marking field that contains the matrix code. For steering the laser to the marking field or for the simultaneous guiding of the light from the marking field to the reading device, a dichroic beam splitter is provided in the beam path.
The German publication DE 103 08 684 A1 discloses a method for the quality inspection of two-dimensional matrix codes on metallic workpieces with an image-processing device. The matrix code is applied in the form of marking dots on the metallic workpieces. The embossing procedure for the marking dots is performed with reference to specified digital position data by a marking tool. Then the corresponding image data for testing is recorded by the image processing device only at the positions specified by the position data.
US Patent application US 2004/0099724 A1 discloses a workpiece with a machine readable data carrier. The data carrier comprises a two-dimensional matrix code. The matrix code is produced on the workpiece by means of holes. A mechanical processing is preferred, because the burn-in process for the code by a laser can lead to structural changes of the material. Before the workpiece is mounted in the holder for the application of the matrix code, the matrix code is checked by a reading device.
DE 100 59 246 A1 is likewise concerned with a marking system in which a radiation source emitting a laser beam is arranged within a housing. In addition, a scanning device that steers the laser beam in a protective housing is located in the housing.
From DE 199 15 071 A1, another marking system is known in which a radiation source is arranged within a protective housing on a guide and not, like in the marking system according to the invention, in a support frame outside of the protective housing.